Pete, I think you'd have to look at doing some finish sanding with CNC or you'd slow down the CNC to a crawl getting the passes close enough to keep the mill marks out of it.
I think a CNC could rough them out fast enough and if you did multiple router heads at once you'd speed that process up quite a bit doing several at once. For the type of grips you showed, you'd still have to have someone sand and smooth them out. You might be able to get away with another sanding method, like put them all on a grid and shoot them with a sand blaster with some soft media.
To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault